Arc furnace control apparatus



March 14, 1933. J. YOUNG mo FURNACE CONTROL APPARATUS Filed May 1, 1951lllllull Patented Mal-.14, 1933 JOE! YOUNG, OI WELLNDQDNTmO, CANADA;

A30 WAGE coma APPARATUS Application ma 1:7 1, 1931. Serial In. sum.

My invention relates to improvements in electric arc furnace controlapparatus and the object of the invention is to provide means forregulating the arc voltage in conjunction with a current regulator sothat each electrode will deliver an equal amount of energy in watts intothe furnace and the tendency of an electrode to dip and remain incontact with the charge in the iurnace will be oh- 9 viated.

in the usual operation of arc furnaces, particularly those operating ona three phase system, dificulty is encountered in regulatinc; theelectric power so that each electrode will deliver an equal amount ofenergy in watts, and the one or other of the electrodes has a tendencyto dip and remain in contact with the metal, so contaminating the chargeand making it dificult to control the carbon content. The employment oimy voltage regulator cures the above dificulties,

A preferred embodiment oi my invention is hereinafter described andillustrated in the r accompanying drawing in which l is a diagrammaticview of a threephase are furnace showing control appa rctus appliedthereto, and

lik 2 is an enlar ed vertical section through my control apparatus Likecharacters of reference indicate corresponding parts in the differentviews.

1 is the bath or hearth, and 2 are the. electrodes. 3 are the furnacebus'hars connected to the respective electrodes 2. Such parts are ofstandard construction as are the current transformers 4 and the circuits5 as well as the circuits 6 including the current regulator solenoidcoil 7. 1

My voltage regulator comprises a base 8 upon which are mounted threesolencid'coils 9, each provided with .a sliding core 1 One terminal wire11 of each-coil 9 is connected through a common lead 12 to the bath orhearth l, and the other terminal wires 13 of the coils are connected tothe respective busbars 3. The solenoid coils 9 are preferably arrangedin triangular formation and a tripod 14 is adapted to rest on thesliding cores 10. The tripod 14 is swingably mounted for tiltingmovement upon a central standard 15,

as for instance, on a ball and socket fulcrum 16, the ball beingprovided with a resilient connection between it and the base 8.

Lead wires 17 and 18 from the respective v transformer circuits 5 areconnected respectively to an insulated contact 19 on the extremity ofeach leg of the tripod l4, and to an adjustable resilient contact 20positioned above each contact 19, said contacts 20 being in engagementwith the contacts 19 when the trigcd is disposed horizontally.

urther standard apparatus is employed which consists of a motor drivenWinch 21 for raising and lowering each electrode individually, currentregulators 22 operating through variations, of current in the bus bars 3throughthe current transformers 4, ma etic switches and 24 which actuateto t ow into circuit the motor driven winch 21 and rotate it in therequired direction either to move the electrodes upwardly or downwardlydepending upon the fluctuations in current in the hue here 3, andrheostats $5 in shunt with the current regulator coils '4' forperinitting' the varying of the current input into each electrode.

Ewing to the complexity of the diagram, in the drawing a winch 21 isonly shown as connected to the third electrode 2 as well as currentregulator 22 connected therewith with the third rheostat '3. Suchapparatus would of coursebe duplicated vnth respect to the first andsecond electrodes 2 and with the first and second rheostats 7 With theexception of my voltage regulator and its connections all the apparatusdescribed above is now in use and it is only the application oi myvoltage regulator to such standard apparatus which constitutes myinvention In operation; each of the three solenoids 9 is energized by ashunt current passingthrough it from a corresponding bus bar 5 allelectrodes the tripod 14 will beina horizontal position, but shouldthere be anyhearth. When the voltage is the same in v variation in thevoltages, the tripod through the action of the solenoids 9 will tiltaway from that solenoid having the least current passingv through it toa degree depending its operation on unbalanced conditions of arc Volta sand the tripod whichcoacts' with the mova le cores responds always tothe resultant of the three forces acting on the solenoids.

Furthermore, it will be seen that should the volta s in the bus bars beraised or lowered t e apparatus will still continue to function and, inthis connection, the windings of the coils!) could be so designed as tooperate over a widerange of voltages.

The apparatus can also'be used to open the electric circuit-of a relayon a-magnetic contalc tor used in the electric winch motors operatingthe electrodes and so keep the electrodes from being lowered into t-hefurnace charge. 7

What I claim as my invention ist 1. In a three-phase arc control aparatus, in combination a furnace hearth, 't rec electrodes, bus barssupplying current to the three electrodes, a current regulatingcircuitincluding a current regulator associated with eachelectrode,and-a shunt circuit ineluding a, rheostat in circuit with each currentregulator, a voltage regulator comprising a magnetic coil connectedbetween each bus bar and, the furnace hearth, a movablemembersuperimposed abovethe coils, a lplurahty of. contacts on the member, aplurality of contacts adapted to coact with the 0011-,

tacts on the member, each pair of coacting contacts bein connected intoa current reg;- ulatmg circuit'and when out of contact with ,each othercausing a further resistance to be inserted into the shunt circuit witha conse- I, rent quent increase of current through the correspondingcurrent regulator, and means due in combinationa furnace hearth, t

lator a voltage re lator comprising a magneticboil connecte between eachbus bar and the furnace hearth, a movable member superimposed above thecoils, a pluralit of contacts on the member, a plurality o contactsadapted to coact with the contacts on the connected into a currentregulatin circuit and when out of contact with each ot er caus ing afurther resistance to: be inserted into the shunt circuit withaconsequent increase member, each pair of coacting contacts being ofcurrent throu h the corresponding current 1 regulator, a sli ingeoreineach magnetic c011 operatively connected to the member and normallyretained in such ition by the energized'coils that each pair of contactsis in engagement, an increase of current through any pair of ma eticcoils with a consequent weakening of t e current in through theremaining coil causing the breaking of the contact between the pair ofcontacts connected in the current regulating circuit assoclated with theweakened coil.'

31 In a three-phase arccontrol apparatus,

ree electrodes, bus bars supplying current to the three electrodes, acurrent regulating circuit including a current regulator associated-with each electrode,;a voltage regulator comprising a magnetic coilconnected between able tripod member superimposed above the coils, aslidable core in each magnetic coll, each operatively connected to a legof the member, a contact on each leg of the member, and a contactnormally ada ted to contact with each contact on the mem r, each pair ofcontacts connected in a current regulating circuit; a a

J OI-Ibl YOUNG. v

to the weakening of the current in amagnetic coil for causing the memberto break contact I between the contacts connected with the cur- Lregulating circuit associated with such 001 2. In a three-phase arccontrol a paratus,

in combination a furnace hearth, t "ree elec- I trodes, bus barssupplying current to the three electrodes, a current regulating circuitincluding a current regulator associated with each electrode and a shuntcircuit including a rheostat in circuit with each current regui -eachbus bar and the furnace hearth, a tilt-

